Sanji wasn't supposed to be a waiter, nor a doctor for some stupid swordsman. Who would he stupid enough to fight Dracule Mihawk, one of the seven warlords of the sea and the world's greatest swordsman? Zoro definitely was. And how stupid was it for Luffy and the waitress to fight those fish people? Incredibly stupid. Still, he saved her, and the boy. The fishman tossed them into the sea to drown, but he wouldn't allow it.